Making a jazz arrangement and the electric bass part won't make any sound

I'm writing an arrangement of "I Can't Give You Anything But Love" and I have a trumpet, piano, and drumset part written and they all sound fine. I wanted to add a bass. So i Started with a contrabass... Put some notes on the page, hit play and there was no audio from that part. So I decided to exchange out the contrabass for an electric bass and the same issue occured. Any suggestions?